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Old 10-11-2011, 01:59 PM   #1
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Default Launch control - misfire under load

Hey guys.
When I built my MS2 a few months ago I never did the MS2 daughterboard mod to enable launch control (http://www.msextra.com/doc/ms2extra/...#mods_daughter)

Well last week I soldered that wire, enabled launch control. Works great... except now I get spikes in AFR under load (car is N/A). I changed the plugs (BKR6E-11) and it still happens. I have COPs, which were installed like 2 weeks ago and I haven't had any issues with it.

I just did a log where I did 2 launches, pulled over, turned off launch control and did a normal launch.

spikes with launch control in 2nd and 3rd gear WOT:


no spikes without launch control, also 2nd and 3rd WOT:


Other things I've done lately was exhintake mod, but haven't had any issues.


log: http://s95367906.onlinehome.us/photo...1_12.16.20.msl
msq: http://s95367906.onlinehome.us/photo...1_12.47.07.msq
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Old 10-11-2011, 02:05 PM   #2
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is flastshift enabled? are you sure you're not enaging launchcut when shifting?

please attach images here so I can see.
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Old 10-11-2011, 02:09 PM   #3
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Flat shift is not enabled. And I hate how PNGs get converted to shitty jpg when attached :(
Attached Thumbnails
Launch control - misfire under load-launch_control_settings.png   Launch control - misfire under load-misfire_launch_control.png   Launch control - misfire under load-misfire_no_launch_control.png  
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Old 10-11-2011, 02:29 PM   #4
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i bet you $10 your launch control is getting activated when you shift and reapply gas.

enable flastshift and ramp up the limiter to 7K or increase your TPS threashold to like +80%
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Old 10-11-2011, 02:51 PM   #5
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Wouldn't that cause *dramatic* changes in the log? All that happens is AFR goes from 12.0 to 13.2 and back to 12.0 in 0.1 seconds.

But I can hear it :(

Here's another log from last night... 3 spikes

also attached both logs (today and yesterday) and tune.
Attached Thumbnails
Launch control - misfire under load-misfire_afr_spikes.jpg  
Attached Files
File Type: msl 2011-10-11_00.29.06_split.msl (354.5 KB, 49 views)
File Type: msl 2011-10-11_12.16.20.msl (425.5 KB, 55 views)
File Type: msq 2011-10-11_12.47.07.msq (78.9 KB, 64 views)
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Old 10-11-2011, 03:07 PM   #6
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oh i see what what youre saying; i miss understood.
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Old 10-11-2011, 04:45 PM   #7
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I thinking it's a hardware issue. I'll post pictures of my MS tonight or tomorrow.

When I first built it, I didn't remove the ST SIGN fuse. A diode burned, which I replaced. Has been working fine ever since, but who knows...?
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Old 10-11-2011, 04:58 PM   #8
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that only matters if you are driving the fuel pump through a TIP125 out to 1C.
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Old 10-11-2011, 05:07 PM   #9
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I am running the fuel pump through a TIP. I fixed it ages ago and it works fine. Le sigh.

Would running more dwell help? (I'm pulling ideas out of my ***). Log shows actual dwell of anywhere from 2.4 @ 12.7 to 2.13 @ 14.4

Ignition & Dwell curve settings

Attached Thumbnails
Launch control - misfire under load-dwell_adjustment.png   Launch control - misfire under load-ignition_settings.png  
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Old 10-13-2011, 12:57 AM   #10
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figured I'm just going to wait till dyno day. also FYI you can't set flat shift engagement point to 7000+, tuner studio won't let you.

I bumped dwell to 2.5ms and that did absolutely nothing.
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